Solar wind protons detected within Magnetic Holes (MHs) and Magnetic Decreases (MDs) are found to be preferentially heated perpendicular to ${vec {bf B}}$0. The MHs/MDs are associated with the phase-steepened edges of nonlinear Alfv¿n waves. The proton anisotropies can lead to the proton cyclotron and mirror mode plasma instabilities. We examine the Ponderomotive Force (PF), a phenomenon due to wave pressure gradients, and show that for this plasma regime and for phase-steepened Alfv¿n waves, the PF proton acceleration/energization will primarily be orthogonal to B0. It is suggested that accelerated ions create the MHs/MDs by a diamagnetic effect.